I find that the units run out of small arms ammo too frequently and therefore the small arms ammo wagons empty quickly. Small arms ammo supply was not a big issue at Gettysburg. Is there a way to mod the ammo depletion rate or change the capacity of the wagons? Thanks

Or maybe you should just not fire so much when you are NOT at the closer ranges?

If you are depleting your ammunition stores then you are quite likely expending far more ammo than the armies did historically. A common event in this system. Or you might just be unlikey with the percentage checks. The first is more likely. Of course you could always just do like a video game and add in a cheat like unlimited life or ....wait for it....unlimited ammo. Why not change all your regiments to A morale.